Airplane-covering material



N. S. CLAY AIRPLANE COVERING MATERTAL Filed Jan. 14, 1921 WITNESSES. INVENTOR ,mkc'w, Nob/e G, a/ay Patented Dec. .16, 1924.

UNITED STATES PATENT OFFICE.

NOBLE S. CLAY, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

AIRPLANE-COVERING MATERIAL.

Application filed January 14, 1921. Serial No. 437,190.

To all whom it may concern.

Be it known that I, NOBLE S. CLAY, a citizen of the United States, and a resident of Wilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Airplane- Covering Materials, of which the following is a specification.

My invention relates to airplane covering material, more especially to a wing and fuselage covering of fibrous material and a binder.

,' Heretofore, airplane covering materials consisted of finely Woven textile fabrics, such as linen, cotton, or silk, which was stretched across the wing and fuselage structure and fastened securely thereto by tacking or sewin To obtain increased rigidity, the stretc ed fabric was treated with socalled dope which had the characteristic of shrinking the fibers, thereby providing a taut smooth surface. Another object of doping the fabric was to preserve it from deterioration.

It was found, however, that fabric treated in this manner was not protected against moisture, atmospheric changes, or the dcstructive effects of the suns rays. The changes induced by these elements deteriorated the fibers, making the cloth flabby and, consequently, increased its resistance to the passage of air thereover. The so-called doping agents commonly'consisted of cellulose acetate or cellulose nitrate. They are not fire resistant, and the cellulose nitrate, especially, is highly inflammable, making the use of it exceedingly dangerous.

My invention obviates these difficulties, it being among the objects thereof to provide an airplane covering material'which is mechanically strong, durable, non-porous, and offers little resistance to air.

It is another object of my invention to provide a covering material that is self-sustaining and does not require tension on the fibers to keep the material taut.

It is a further object of this invention to provide fireproof covering materal for the parts of airplane structures exposed :to the dangers of heat and flame.

It is a still further object of my invention to provide means for molding thin sheets of fibrous material adapted for use as airplane covering.

In practising my invention, I utilize finely woven linen, cotton or other fabric which may be superposed in multiple layers, with the weave staggered to obtain maximum strength and sewed together, or-I may utilize a single layer of fabric of a heavier weave. I may also employ composite materials, such as combinations of asbestos and fabric. The individual or multiple layers of material are impregnated with a binder, preferably a phenolic condensation product, and molded under heat and pressure. When it is desired to obtain colored material, I employ a colorless phenolic condensation product as a binder so that the molded sheet retains the original color of the fibrous sheet material, which color may be natural or artificially applied thereto. The materials above mentioned may be treated with fire roofing agents, such as inorganic salt solutions, be fore impregnating with the binding material.

The accompanying drawing, formin a part hereof, is a diagrammat1c view 0 an apparatus adapted for molding thin sheets in accordance with this invention.

I provide a roll 1 of fibrous sheet material 2 impregnated with a binder, preferably a phenolic condensation product, which is placed in suitable relation to a number of rolls 3, 4, 5 and6 co-operating with a pair of endless guide belts 7 and 8, passing over guide wheels 9 and 1.0, respectively.

The endless guide belt 7 passes around the pressure roll 3, over the roll 4, around the roll 5 and over guide wheel 9. The endless guide belt 8 passes around the roll 4, over the roll 5, around the roll 6 and over the guide wheel 10.

The guide belts 7 and 8 form a pressure platen arrangement for the sheet material to be molded. The rolls 3 and 4 are heated and 5 and 6 are cooled to alternately heat and cool the guide belts in passing therethrough.

The treated sheet material 2 consisting of one or more layers is inserted between the enga ing surface of the guide bolts 7 and 8 am? is passed between the heated pressure rolls 3 and 4, around the heated roll 4 and the cooled rolls 5 and 6, compacting the material to a hardened unitary layer which is wound on the roll 11.

Although I have described a specific embodiment of In invention, it will be obvious to those skilled in the art that I may emphenolic condensation product, I may employ other suitable binders, such as shellac, albumen, casein or blood glues of desirable quality. Instead of superposing a plurality of layers of fibrous sheet material to form the desired thickness, I may utilize a multiple ply cloth, such as three-ply balloon cloth or other standard airplane covering.

It will be readily seen that my invention provides a simple and continuous process for producing elongate bodies of molded sheet material. The material so produced has numerous advantages over substances heretofore employed for airplane covering, the mostnotable of these being the following: It is non-hygroscopic, is not affected by high temperatures, does not fuse, will not deteriorate under atmospheric changes and is mechanically superior to materials heretofore employed.

I claim as my invention 1. In an apparatus for molding, a series of pairs of pressure rolls co-operating with a pair of endless guide belts, and means for heating and cooling certain of said rolls.

2. In an apparatus for molding, a series of pressure rolls, a pair of co-operating guide belts passing around and between said pressure rolls, and means for heating the first and cooling the last of said rolls.

3. The method of molding an elongate body of fibrous sheet material which comprises passing treated sheet material between the surfaces of a pair of endless guide belts co-operating with a series of pairs of pressure rolls, some of which are heated and others cooled.

4. A method of molding an elongate body of fibrous sheet material -which comprises passing a plurality of sheets of treated material between the .surfaces of a pair of endless guide belts co-operating with a series of pairs of pressure rolls, some of which are heated and other cooled.

5. A method of molding an elongate body of fibrous sheet material which comprises passing sheet material impregnated with a phenolic condensation product between the surfaces of a pair of endless guide belts c0- operating with a series of'pressure rolls, some of which are heated and others cooled.

6. A method of molding an elongate body of fibrous sheet material which comprises passing asbestos paper and fabric impregnated with a phenolic condensation product between the surfaces of a pair of endless guide belts co-operating. with a series of pressure rolls, some of which are heated and others cooled.

7 A method of molding an elongate body of fibrous sheet material which comprises passing sheet material treated with a solution of an inorganic salt and impregnated with a phenolic condensation product between the surfaces of a pair of endless guide belts co-operating with a series of pressure rolls, some of which are heated and others cooled.

In testimony whereof, I have hereunto subscribed my namethis 5th day of Jannary, 1921.

- NOBLE S. CLAY. 

